Motor-control system.



UNITED STATES PATENT OFFICE.

WALTER J. RICHARDS, OF NOR-WOOD, OHIO, ASSIGNOR TO ALL'lS-CHALMERS COMPANY, A

CORPORATION OF NEW JERSEY.

Mo'ronfcoN'rnoL sYs'r'EM.

Specication of Letters Patent.

Patented Dec. 3, 1907.

Application filed April 29. 1907. Serial No. 370.980.

T o all whom it may concern.

citizen of the United States, residing at Nori wood, in the county of Hamilton and State of Ohio, have invented certain new and useful Improvements in Motor-Control Systems, of which the following is a full, clear, and exact specification.

My invention relates to motor control systems and particularly to the automatic control of motors for operating the lifting tables of rolling mills.

In the operation of three-high rolling mills it-is necessary to raise and lower the tables which receive and support the material to, be rolled on either side of the rolls themselves. Generally heretofore this movement of the lifting tables has been obtained by means of steam envinesor other uid operated mechamsm.

tive power. So far as v am aware, however, no scheme has yet been devised for obtaining the proper movement of the lifting tables of three-high rolling mills by electric motors, for these tables not only require a reciprocating movement but must be stopped very accurately in order to allow the ingot to be caught by the rolls. ,It is the ob'ect of my invention to provide a system of electrical drive for these tables whereby their proper operation is insured and to a great extent rendered automatic; Although designed with this ob'ect in view,- my invention is also applicabfe for many other uses.

-My invention broadly comprises the comblnation of an electric motor, and acontroller therefor arranged to make automatically a complete c cle while the motor makes a predetermine number of rotations. Somewhat more specificall com rises the combination ofa motor, a rotata le member driven thereby, a reciprodirection controls the amount of resistancel in a local circuit su plied .by the motor operating as a braking ynamo. rs

Other features of my inventionwill appear l3nt in many modern rolling mills' now belng lnstalled it is being found desirable to substitute electricit for steam as a mo`v sake of simplicity this train o my invention l from the description and drawings and will be particularly pointed out in the claims.

Figure 1 shows diagrammatically one embodiment of my invention; and Fig. 2 shows a cross section of the magnetic brake.

The three rolls 10, 11 and 12 of a threehigh rolling mill may be driven in any desired manner. Lifting tables 12 and 13 are arranged in the usual manner on each side of these rolls to receive ,and support the ingot, bloom or billet 14 to be rolled, and may be raised and lowered-to bring the ingot 14 between the rolls 10 and 11 or between the rolls 11 and 12. This is accomplished through bell-crank levers 15 connected 4to the supports of said tables and joined to a gear wheel 16 by means of `a connecti rod 16. Onehalf rotation of the gear whee 16 raises the tables 12 and 13 and the next half'rotation lowers said tables. Another ear wheel 17 is arranged to move at twice t e angular speed of the gear wheel 16, both of these gear wheels being drivenl by a. motor 18 throu h any suitable train of geariL 19. For t e gearing is here represente by a single gear wheel. A magnetic brake 20 lcooperates with the gear 19 or with some other of the parts driven by the r'lotor 18 andwhen energized tends to stop 4said motor and all of the parts driven thereby.

The effect of the magnetic brake may be reguiated by a rheostat 21. The field 22 of the motor 18 ma' be reversed by the reversing switch 23.- he motor is controlled by means of the controller 24:,l the reciprocable arm25 of which is arranged to be driven from the gear 17 through suitable connecting mechanism 26, thearm 25 making a complete reciprocation for each rotation 'of the ear 17. Preferably the connecti mechanismV 26 is so-arranged that it may e disconnected from the ear 17.

The current or the various electrically operated devices may be obtained from any desired source, as throu h the switch 27. When this switch is close and the arm 25 is in its lowest position the motor may be started by depressing the button l28, thus moving the switch 29 to its up er 'position to complete the circuit through t e solenoids 30 and 31. The formerwhen energized. raises or holds raised the switch 29, while the solen-` oid 31 raises the switch 3 2` Unless Vthe arm 25 is in off position the sector 33 which is attached to said arm keeps the button 28 fromy pletes the circuit of 4the amature 18 throu h5: -the bar 34, arm 25 and resistance 35. T e

field circuit of the'motor is always complete when the switches 27 and '23 are closed, but movement' of the arm 25 cuts the resistance 36 into and out of said ield'circu'it As soon as' the armature 'circuit ofthe motor isocomf` pleted said motor `begins to drive the gear wheels V19, 17, and 16, mol the tables 12 and 13 either up or down as t el case may be. and the arm' 25 rst up and .then down. Asthe arm moves upward it gradually cuts tlleresiatance out of the armature circuit the resistan'sS into t e motlil' ield .circul't tohelp int :speeding u w e ving-t e motor a strong ltield" for I1 )ts startg'. The last section 37 of ytheresistance'35 is adjustableto regulate .the acceleration, lboth posi,

tive'and'negativarof the motor'18. q

tarily 'cut out of the field circuit to raise the l When the' resistance' 35 has been com.l

i pletely cut out 'the resistance '36f-is'n1ome`ncounter-electromotive force of the motor. While the resistance 36 is in circuit, thearrn 25 leaves the contact` bar 38 to break the circuitof the'solenoids 30 and 31, thus allowmgthe switches 29 and 32 to dro 'to their lower position. The. dropping-oft e switch 29'connects in circuit the magnetic brake 20 35 with its rheostat 21, and ofthe switch 32"disconnects the motor armature from its'suppl circuit and connects it upon itself throug Vthe solenoid 39 and the resistance'` 35' so-that it will actfas abraking dynamo. -On account oftheincroased electroinotive 'forceof the motorverylittle current' is `ilo.

arcing as the switc 32 breaksthemotor armature circuiti The-solenoid; 39 closes 4'of the resistance 35 ma' be above' the 'arm 25 ou 1 f `retarded-b the action of the magnetic brake 19""and o the braking dynamo 18. The

at any; point in the esce'n't of1 the latter.' The arm.'25 has now reached its uppermost 'position-and has begun its vdescent:- 'While 1t is de'seending-themovingparts are being effect of .the latter is'xmainta'ined approxi- Y mately'constantbecaus'e'on account ofthe connection made by .tliesvv'itch 40 the dei scent of the -arm 25. cuts' the resistance' 3 5 gradu y out `of the local circuit supplied'b said armature. local circuit extends from theY armature '18, throu h thel switch xarm 25 at any time,falongftl`\e.arm 25- t'ogthe cause said motor to s eed up. It also cuts at vthisvtime and 'conseqlllientlythereis but' -ttle the switch 40 to shortfcircluit whatever part' :pendently -of-` the z'aforesaid' means.

- combination, an electric motor-, a *.sour'cefof lcurrent'supply, a variable resistl ance, a1 reciprocablearmfor varyingV said g. .resistance-,f and" connections controlled` by said wherebymovement of the same in ,sain its lower position, 'the so noid 39, that part vof the resistance 35 which below" the extreme lowery or upper positions as the case may be, the motor 18 and other movin arts have been brought to a stand-sti en necessary'. the operator can control this stoppin p'oint -to some extent by the rheostat 21 ut generally this rheostat and the resistance section 37 may beA permanently. adjusted to obtain the stopping of the motor at the desired point automatically. As soon as the motor 18 has stopped, the solenoid 39 is dener lzed and the switch 40 is allowed to open. he ingot ma now be sent through the rolls after which t e opera'.- tion above described may berepeated by depressing the push-button 28. v

Shou d it ever be necessary or desirable to obtain less than'complete movements of the movable the switc 41 into the position shown 1n dotted'lines to energize the solenoids 30-and 3l.

' as said switch remains in such position lo 'ariiwill stop asl soon after itis moved away therefrom as the various brakingdevices are able to obtain their effect.

The various parts of the resistance'35 may p'lartsthis'may be done by moving The movement will then continue as be proportioned to allow for the different rates' o speed.' of the arm 25 'in the' different parts of its movement. Or if desired the 'connecting mechanism 26 may be arranged to cause" a substantially uniform speed of said arm. By means of the switches 23 and 41'backward movement of the motor maybe obtained when necessary. 'Various modifications in .the precise vsystem'here shown and described may be made without departing from the spirit and scope ,of my invention vand the control system shown may be ap lied to other uses `than for the operation `o rolling mill tables. All,

such modifications and 'uses I aim to cover in the following claims.' 'What I claim as new is A rheostat comprising a plurality .of reslstance sectlons, means for cutting saidv sections lnto vand vout of circuit, and independent means of varying one-of said sections. f ;.l v 2. In comblnatlon, a sectlonal reslstance,

.the resistance of and, a` relativel movable arm for cutting' sectionsV of sai :resistance into and out of ,circuit,.- one of the resistance sections controlledby said arm being adjustable.

3. In combination, an' electric motor, a

the'armature circuit, and means for varying sectional resistance, means 'forV cutting the sections of sa1d resistance 1nto and out of the resistancefof-one of 'said sections inde.

one direction varies the amount of said resistance in circuit with the motor and said source ol' supply in series, and movement in the other direc-tion varies the amount of said resistance in circuit with the motor alone.

5. In combination, an electric motor, and a reciprocable controller therefor arranged when moved in one direction to vary the electromotive force impressed on the motor armature, and when moved in the other direction over the same path to vary the resistance in a local circuit supplied by the motor armature. Y y

6. In combination, an electric motor, a rotary member driven thereby, and means for controlling the electromotive force impressed on the motor armaturel during one portion of a rotation of said member and for controlling the action of the Amotor as a braking dynamo during the remainder of said rotation.

7. In, combination, an electric motor, mechanism driven thereby, and a controller for the motor also driven thereby and arranged to make a complete cycle for each half cycle of the driven mechanism.

8. In combination, an electric motor,

l mechanism driven thereby, and a controller also driven'thercby and arranged to make a plurality of 'complete cycles foreach complete cycle of the driven mechanlsm.

9. In combination, an electric motor, and

a controller therefor arranged to make automatically a complete cycle while the motor makes a predetermined number of rotations in the same direction.

10., The combination of a motor, and" a controller therefor arrangedas it is moved in one direction to control the electromotive force impressed on the motor andas it is moved over the same path in the other direction to control the action of the Inotor as a braking dynamo in discharging through a local circuit.

11. The combination of a motor, a rotatable member driven thereby, a reci rocable controller for the motor arrange to be moved by said rotatable member, vand connections whereby the movement of said controller in one' direction controls the electromotive torce lmpressed upon the' armature of the motor, and movement in the other dii frection controls the' amount of resistance in a local circuit supplied by the motor armature as a braking dynamo.

12. In combination, an electric motor, a magnetically operated switch in the motor armature circuit, and a reciprocable controller which as'it is moved in one direction controls the resistance in 'the arma ure circuit and when it reaches its limit of overnent in this direction causes the opening of said switch.

13. In combination, an electric motor, a magnetically operated switch in the motor armature circuit, and a reciprocable controller which as itis moved in one direction controls the resistance inthe armature circuit and when it reaches a predetermined ointv in its movement'causes the opening o said switch.

14. In combination, an electric motor, a magnetically operated switclrin the motor armature circuit, and a reci rocable controller driven by the motor an arran ed when moved in one direction to control t e resistance in the armature circuit and. when it reaches a predetermined point in its movement to cause the opening of said switch.

15. In combination, an electric motor, a

Imagnetically operated switch arranged when vary the electromotive force impressed .on

the armature and when it reaches its limit of movement in this direction to cause movement of said switch to connect the'armature upon itself.

16. In combination, an elec-tric motor, a magnetically operated switch arranged when in one position to complete the motor armature circuit and when 1n another position to connect the armature on itself and a reciprocable controller arranged when moved 1n one direction to varythe electromotive force impressed on the'motor armature and when it reaches its limit of movement in this direction vto cause movement of said switch to connect the armature upon itself.

17. ,In combination, an electric motor, al

the motor and ,arranged `when moved in either direction to vary the resistance in the motor armature clrcult and when 1t reaches -its limit `of movement in one direction to cause movement of said switch from one position to the other. g

18. In combination, an electric motor', a magnetically operated switch arranged-when in one position to connect the motor to a' source of current supply and when in another position to connectA the motor armature upon itself, and a reciprocable controller arranged when moved in either direction to vary the resistance in the motor armature circuit and when it reaches its limit of movement in one direction to cause movement of said switch from one position to the other.

19. In combination, an electric-motor, an electric brake therefor, a magnetically operated switch arranged when in one posltion to control the motor armature circuit and when lin another position to control the electric 5 reaches the limit of movement said direc-4 tlon to cause movement of said switch tocom lete the brake circuit, and means for drivm said controller from the motor.

20. n combination, an electric motor, an electric brake therefor, a magnetically operated switch arranged when in one positionto control the motor armature circuit and when in. another position to control the electric brake circuit, and a reci rocable controller for the motor arranged w en it is moved in one direction to vary the electromotive force impressed on the motor armature and when it reaches the limit of movement'in said direction to cause movement of said switch to complete the brake circuit. 4121. In combination, an electric motor, an electric brake therefor, a-magnetically operated switch arranged .when in one position to control the motor armature circuit and whenin another position to control the electric brake circuit, va reciprocable controller for the motor and driven thereby arranged when it 1s moved 1n one direction to vary the electromotiveforce impressed on themotor armature and when it reaches the limit offmovement in said direction to cause movement of said switch to complete the brake circuit, and means ,for varying the effect of said brake.

22. In combination, an electric motor, an electric brake therefor, a magnetically operated switch arranged when in one posltion to controLthe motorlarmatre circuit and when in another position to control the electric brake circuit, a'reciprocable controller for the motor arranged when it is moved in one direction tovary the electromotive force impressed on the motor1 armature and when it reaches the limit of movement in said direc-A tion to cause movement of said switch to com lete the brake circuit, and means 'for `regnating the effect of said brake.`

23. In combination,1an electric motor, a magnetically operatedswitch in the motor armature clrcult, a reciprocable controller which as it is moved in one direction .controls the resistance. in the armature circuit,`and when it reaches its limit of movement inv this direction causes the openin o'f said switch, and connections whereby t e controller increases the field strength of the motor while said switch is being opened.

24. iIn' combination, 'a'n electric motor, a magnetically operated switch arranged when in one position to complete the motor-armature circuit and when .in another position to connect. the armature' on itself, a reciprocable controller arranged -when moved in one direction to vary the electromotive force impressed on themotor armature circuit and when it reaches its limit of movement in this.

direction to cause movement of'said switch to lconnect the armature upon itself, and.

connections wherebythe controller causes an increase inthe counter-electromotive force of the motor'whjle said switch is being somoved."

25. In combination, an electric motor, a

magnetically operated switch arranged when' 1n 011e position to connect the motor to a source of current supply and when in another position to ,connect the motoraarm.- ture u pon itself, a reciprocable controller arrange when moved 1n either direction to vary the resistancemin the motor armature circuit and when it reaches the limit of movement in one direction'to cause movement of' said switch from one position to the' other, and connections whereby the controller 1ncreases the field strength ofthe 4motor while said switch is being so moved. 26. In combination, an 'electric motor, a

magneticallyf operated switch arranged when in one position to connect the motor to a source of current supply and when 1n another. position to` connect the motor armacontrol the motor armature circuit and when A in another position to controlthe electric brake circuit, -a reciprocable controller for the motor arranged when itis moved in one directiorf to vary the electromotive force im-v 'pressed on the motor armature c1rcu1t and when it reaches the limit of movement in said direction to. ca'use-` movement ofsaid` switch to com lete the brake circuit, and connections w ereby the controller increases the fieldstrength of the motor While said switch is being'so moved.

28. The combination in a rolling mill, of a lifting table,`v a motor for operating said lift, in'g table, and means for controlling said motor in response to thefmovement ofthe lifting table.

29. The combination in -a rolling mill, of a and a controller operated by the movement of' said table to stop the motor at each of its extreme positions.

'30. The combination-in a rolling mill, of a lifting table,lelectricallr operated means for lifting table, a motor for operating said table,

raising and lowering saidtable, and means A for automatically controlling the aforesaid means.

Imovement of the lifting tab'le to control .the

the action of said motor as a braking dynamo.

31. The -combination in a rolling mill, of a 1 lifting table, an electric motor for operating 15 lifting table, electrically operated means for said table, and means o erated by skaid moraising and lowering said table, and means tor and arranged as sai table leaves one of operated by and controlling the aforesaid its extreme positions to control the electrical means. energy supplied to said motor and as said 32. The combination in a rolling millfof a table approaches the other extreme position 2`0 lifting table7 an electric motor for operating to control the braking effect on said motor. said table, and an automatic controller for In testimony whereof I aix mysig'natiire, lslaid motor arranged during part of each nin the presence of two witnesses. supply of electrical energy to said motor and WALTER J' RICHARDS' during the rest of the movement to control v Witnesses:

GEO. B. SCHLEY,

33. The combination in a rolling mill, of a FRED J. KINSEYL 

